armv8: Fix defconfig build

Commit 14f48861 ("arc: Add ARC and ARC BE architecture") introduced a
sed match against arc* buildroot architecture to translate it to arc.

This causes a problem with armv8, which is called in buildroot aarch64,
which is also matching, resulting in a build failure.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

Makefile

@@ -238,7 +238,8 @@ ARCH:=$(call qstrip,$(BR2_ARCH))
 
 KERNEL_ARCH:=$(shell echo "$(ARCH)" | sed -e "s/-.*//" \
 	-e s/i.86/i386/ -e s/sun4u/sparc64/ \
-	-e s/arc.*/arc/ \
+	-e s/arcle/arc/ \
+	-e s/arcbe/arc/ \
 	-e s/arm.*/arm/ -e s/sa110/arm/ \
 	-e s/aarch64/arm64/ \
 	-e s/bfin/blackfin/ \